How do you find the zeros of #y=x^3-10x-12#?

1 Answer
Jan 26, 2018

Answer:

Zeros are #x =-2 , x= -1.65 and x= 3.65#

Explanation:

#y=x^3-10x-12# or

#y = x^3+2x^2-2x^2-4x-6x-12 # or

#y = x^2(x+2)-2x(x+2)-6(x+2)# or

#y = (x+2)(x^2-2x-6):. x=-2# is one zero

#x^2-2x-6= 0 or x^2-2x=6 # or

#x^2-2x+1=6+1 # or

#(x-1)^2=7 or (x-1)=+-sqrt 7# or

#x=1+-2.65 :. x~~ 3.65 , x = -1.65#

#:. y=x^3-10x-12= (x+2)(x+1.65)(x-3.65)#

Zeros are #x =-2 , x= -1.65 and x= 3.65# [Ans]